Added Action.fcurves.find(data_path, array_index=0)

Finding a specific F-Curve is often needed in Python, and usually
consists of a construct like:

```
 [fcurve
  for fcurve in ob.animation_data.action.fcurves
  if fcurve.data_path == "location"][1]
```

This can now be written as
`ob.animation_data.action.fcurves.find('location', 1)`

This new function `Action.fcurves.find()` is still O(N) in the number
of FCurves in the Action, but at least it allows us to remove
boiler-plate code. It is also faster than the Python equivalent, as
only the found F-Curve is converted to Python.

Reviewers: campbellbarton, aligorith

Reviewed By: aligorith

Differential Revision: https://developer.blender.org/D1427

1 files changed, 24 insertions, 0 deletions

diff --git a/source/blender/makesrna/intern/rna_action.c b/source/blender/makesrna/intern/rna_action.c
index d121e1f5cfc..424e2004749 100644
--- a/source/blender/makesrna/intern/rna_action.c
+++ b/source/blender/makesrna/intern/rna_action.c
@@ -119,6 +119,17 @@ static FCurve *rna_Action_fcurve_new(bAction *act, ReportList *reports, const ch
 	return verify_fcurve(act, group, NULL, data_path, index, 1);
 }
 
+static FCurve *rna_Action_fcurve_find(bAction *act, ReportList *reports, const char *data_path, int index)
+{
+	if (data_path[0] == '\0') {
+		BKE_report(reports, RPT_ERROR, "F-Curve data path empty, invalid argument");
+		return NULL;
+	}
+
+	/* Returns NULL if not found. */
+	return list_find_fcurve(&act->curves, data_path, index);
+}
+
 static void rna_Action_fcurve_remove(bAction *act, ReportList *reports, PointerRNA *fcu_ptr)
 {
 	FCurve *fcu = fcu_ptr->data;
@@ -576,6 +587,7 @@ static void rna_def_action_fcurves(BlenderRNA *brna, PropertyRNA *cprop)
 	RNA_def_struct_sdna(srna, "bAction");
 	RNA_def_struct_ui_text(srna, "Action F-Curves", "Collection of action F-Curves");
 
+	/* Action.fcurves.new(...) */
 	func = RNA_def_function(srna, "new", "rna_Action_fcurve_new");
 	RNA_def_function_ui_description(func, "Add an F-Curve to the action");
 	RNA_def_function_flag(func, FUNC_USE_REPORTS);
@@ -587,7 +599,19 @@ static void rna_def_action_fcurves(BlenderRNA *brna, PropertyRNA *cprop)
 	parm = RNA_def_pointer(func, "fcurve", "FCurve", "", "Newly created F-Curve");
 	RNA_def_function_return(func, parm);
 
+	/* Action.fcurves.find(...) */
+	func = RNA_def_function(srna, "find", "rna_Action_fcurve_find");
+	RNA_def_function_ui_description(func, "Find an F-Curve. Note that this function performs a linear scan "
+	                                "of all F-Curves in the action.");
+	RNA_def_function_flag(func, FUNC_USE_REPORTS);
+	parm = RNA_def_string(func, "data_path", NULL, 0, "Data Path", "F-Curve data path");
+	RNA_def_property_flag(parm, PROP_REQUIRED);
+	RNA_def_int(func, "index", 0, 0, INT_MAX, "Index", "Array index", 0, INT_MAX);
+
+	parm = RNA_def_pointer(func, "fcurve", "FCurve", "", "The found F-Curve, or None if it doesn't exist");
+	RNA_def_function_return(func, parm);
 
+	/* Action.fcurves.remove(...) */
 	func = RNA_def_function(srna, "remove", "rna_Action_fcurve_remove");
 	RNA_def_function_ui_description(func, "Remove action group");
 	RNA_def_function_flag(func, FUNC_USE_REPORTS);